Apparatus for testing pressurized containers

ABSTRACT

A succession of pressurized containers are delivered by a conveyor band to a heating station, a rotary feeding wheel receives the containers from the conveyor band in peripheral pockets, and a rotary star wheel is arranged in tangential relationship to the feeding wheel to receive the successive containers in peripheral chambers from the feeding wheel. The containers are held in the chambers, while the chambers are sealed, until the respective chambers have almost reached the feeding wheel after almost a full rotation of the star wheel, and then the containers are removed from the chambers of the star wheel after their fluid tightness has been tested.

United States Patent [191 Waldherr 51 May 1,1973

[ APPARATUS FOR TESTING PRESSURIZED CONTAINERS [73] Assignee Johann Waldherr OHS, Mannheim,

Germany [22 Filed: Apr. 24, 1972 21 Appl. No.: 246,643

[30] Foreign Application Priority Data [56] References Cited UNITED STATES PATENTS 1,163,962 l/l927 Schworetzky 3,590,256 6/l97l Neeff et a1 ..73/52 Primary Examiner-Herbert Goldstein Attorney-Kurt Kelman 5 7] ABSTRACT A succession of pressurized containers are delivered by a conveyor band to a heating station, a rotary feeding wheel receives the containers from the conveyor band in peripheral pockets, and a rotary star wheel is arranged in tangential relationship to the feeding wheel to receive the successive containers in peripheral chambers from the feeding wheel. The containers are held in the chambers, while the chambers are sealed, until the respective chambers have almost reached the feeding wheel after almost a full rotation of the star wheel, and then the containers are removed from the chambers of the star wheel after their fluid tightness has been tested.

16 Claims, 16 Drawing Figures Patehted May 1, 1973 8 Sheets-Sheet 1 P aten td "May 1 1973. 3,129,984

8 SheetsSheet 2 Patented May 1,; 1973 3,729,984 j 8 Sheets-Sheet 5 Patented May 1, 1973' 3,729,984

8 Sheets-Sheet 4 Patented May 1, 1913 I 8 Sheets-Sheet 6 Patented May 1, 1973 8 Sheets-Sheet H APPARATUS FOR TESTING PRESSURIZED CONTAINERS The present invention relates to improvements in an apparatus for testing the pressure resistance and fluid tightness of a succession of containers filled with a fluid under pressure, such as aerosol cans.

Pressurized containers, such as aerosol spray cans or other types of containers filled with a gaseous fluid under pressure, require testing of their pressure resistance and fluid tightness to comply with the law. For this purpose, the contents of the containers must be heated to about 50C., causing the internal pressure to rise from about 2.5 atmospheres at room temperature to 6.5 atmospheres at the elevated temperature.

In conventional testing apparatus, the heating means for the containers to be tested is usually a hot water bath wherein the containers are immersed and conveyed. Those tested containers which cannot withstand an internal pressure of about 6.5 atmospheres burst, and any containers which are not fluid tight under the increased internal pressures will cause gas bubbles to be formed in the water bath to indicate the faulty containers. Several operators are posted at various points of the water bath to make visual observations and remove the faulty cans.

Since the containers are fully immersed in the test bath, the water must be removed from any crevices and/or the valves of the containers after the testing. This is a timeconsuming operation, not to speak of the lack of reliability of the test results since it depends entirely on the carefulness of the operators. In addition,

the operators are subjected to thedanger of exploding cans as they remove the faulty containers from the bath by hand.

The containers may be of steel, tin plate, aluminum or glass, for instance, requiring various means to keep the containers immersed in the test bath while they are conveyed therethrough. Such means include magnets, clamps, holding tongues or grippers, and the like, many of these mechanisms being complex and, therefore, subject to damage after long operation under water.

It is one object of this invention to provide a testing apparatus for pressurized containers wherein the containers need not be fully immersed in an aqueous testing bath and wherein the testing is effected mechanically and automatically.

The above and other objects are accomplished in accordance with the invention by providing a heating means for the containers for elevating the temperature of the fluid in the containers and means for testing the fluid tightness of the containers in a testing zone arranged subsequent to the heating means. A first conveyor means, such as a conveyor band, conveys a succession of the containers through the heating means for a time sufficient to permit the fluid temperature to be elevated. A container feeding means, such as a rotary feeding wheel having a succession of pockets arranged about the periphery of the feeding wheel, receives the containers in succession from the first conveyor means. A second conveyor means, such as a star wheel rotating in a direction opposite to that of the feeding wheel, is arranged in substantially tangential relationship to the container feeding means and has a succession of chambers arranged peripherally for receiving successive containers from the feeding means. The second conveyor means revolves to move the chambers in a closed path and through the testing zone. Means is arranged for holding the successive containers in the respective successive chambers and for sealing the chambers at least in the testing zone, and means is arranged for removing the tested containers from the respective chambers beyond the testing zone.

The above and other objects, advantages and features of thepresent invention will become more apparent from the following detailed description of certain now preferred embodiments, taken in conjunction with the accompanying drawing wherein FIG. I is a schematic elevational view of the means for testing the fluid tightness of the containers according to one embodiment;

FIG. 2 is an enlarged, simplified showing of the arrangement of FIG. 1;

FIG. 3 is a view similar to that of FIG. 1 and showing a modified arrangement;

FIG. 4 is another view similar to that of FIG. 1 and showing yet another modification;

FIG. 4a shows a detail of the arrangement of FIG. 4;

FIG. 5 illustrates another embodiment;

FIGS. 6 to 8 illustrate, respectively, a side view, a top view and an end view of a complete testing apparatus according to this invention;

FIG. 9 is a top view showing the cooperation of the feeding wheel and the star wheel;

FIG. 10 is an elevational side view, partly in section, of the arrangement of FIG. 9;

FIG. 1 l is a top view of another embodiment of a star wheel, with cooperating portions of the apparatus;

FIG. 12 is an elevational side view, partly in section, of a detail of the arrangement of FIG. 1 1;

FIG. 13 is a side elevational view of a portion of the periphery of the star wheel of FIG. 1 1;

FIG. 14 is a top view, partly in section, of a detail of the arrangement of FIG. 1 l; and

FIG. 15 is an end view of the detail of FIG. 14.

To simplify the description, like reference numerals designate like parts functioning in a like manner in all figures of the drawing.

Referring now to the drawing and first to FIGS. 6 to 8, the illustrated heating means for the containers 1 to be tested comprises an elongated trough 2 containing hot water. A downwardly inclined plane or chute 14 at an inlet end of the trough guides and. delivers a succession of containers I to the bottom of the trough where a meandering conveyor band 13 is arranged, with a plurality of runs going back and forth from one end of the trough to the other so as to convey the containers through the hot water for an extended period of time sufficiently to heat the contents of the containers to about 50 to C., or any other desired elevated tern perature. At the other end of the conveyor band, there is arranged another inclined plane or chute l5 whereon the containers delivered from the conveyor band rise towards feeding wheel 6.

As shown, the trough may be covered by a hood 9 to prevent escape of steam or of gases escaping from burst containers, and a flue may be connected to the hood to receive such steam and gases. The hood may be of transparent plastic or like transparent material to enable visual observation of the interior of the trough.

The bottom of the trough is covered with enough hot water to immerse the containers only partially therein,

which makes it necessary to control the water level in the trough according to the volume of the totality of containers being conveyed through the water bath. This may be effected by providing an overflow of a predetermined height in the trough, the overflow being in communication with an auxiliary trough 4 receiving excess water from trough 2. If desired, an automatic water level control may pump the water from the auxiliary trough 4 back into the heating trough 2, and it may be useful to insert a filter into the circulating line to purify the water which may have been polluted by the containers to be tested.

As most clearly shown in FIGS. 1 to 4, rotary feeding wheel 6 has a succession of pockets arranged about the periphery of the feeding wheel for receiving successive containers 1 from chute 15. The feeding wheel rotates clockwise and each container pushed into a respective pocket is taken along by the rotating wheel for about half a rotation of the wheel to transfer the container at a substantially diametrically opposite point to a chamber 7 of the star wheel 8 which is rotated in a counter-clockwise direction to take along a respective one of the containers transferred from a pocket of the feeding wheel into an associated chamber of the star wheel or turnstile 8, the container projecting radially out of the pocket into the chamber. This transfer, best shown in FIG. 2, is made possible by the substantially tangential relationship between feeding wheel 6 and star wheel 8.

The star wheel has a succession of chambers arranged about the periphery of the star wheel for receiving the successive containers 1 from pockets 5 of the feeding wheel, and means is provided for holding the successive containers in respective chambers 7 and for sealing the chambers about a large portion of the periphery of the star wheel until the respective chamber has almost reached the feeding wheel again after almost a full rotation of the star wheel. As best shown in FIG. 9, means is provided for removing the containers from their respective chambers when they have almost reached the feeding wheel after almost a full rotation.

Over the large portion of the periphery of the star wheel or turnstile, the chambers 7 are substantially completely sealed so that these chambers are filled with any escaping gaseous fluid from leaking containers in such chambers. In a testing zone C along the periphery of the star wheel, gas detecting means are associated with the chambers to detect the presence of any such escaping gases in the chambers and thus to determine leaking or faulty containers. As will be explained in more detail hereinbelow, a support base for the star wheel provides a bottom sealing means for the chambers, and one or more gas detectors are mounted adjacent lateral sealing walls in the testing zone, which are connectable selectively to a central indicating instrument. When such a gas detector has detected traces of gas and has transmitted a test signal to the indicating instrument, it must be regenerated for a certain period of time. Therefore, a plurality of detectors are provided so that a different detector may be connected to the indicating instrument while another detector is being regenerated.

Any chamber which housed a leaking container will be filled with escaping gas. To avoid false readings,

means is provided in peripheral zones A and B (see FIG. 2), which precede and follow the testing zone, to remove all such gases from the chambers. For this purpose, the chambers are kept laterally open in zones A and B to enable residual gases in the chambers to be blown out of the chambers in these zones, for instance by means of air nozzles.

The lateral sealing walls for the container storing chambers 7 of star wheel 8 may consist of a fixed sealing band 20, as shown in FIGS. 1 and 7, one end 21 of the band being fixedly held while the other end of the band is resiliently held to exert tension upon the band, the illustrated resilient holding means being a pneumatic jack 22. In this manner, the sealing band is pressed laterally against the periphery of the star wheel.

In the modification of FIG. 3, the sealing band 24 is supported by guide rollers for movement of the band with the rotating star wheel, i.e. the endless sealing band 24, trained about a series of guide rollers, moves along the periphery of the star wheel as the same is rotated and preferably at about the same speed so that there is substantially no relative movement between the rotating wheel and the moving band.

While the testing arrangements 3 of FIGS. 1 to 3 have been shown in conjunction with lateral sealing bands, and upright polished sealing segment 25 is mounted in sealing engagement with the star wheel chambers about a large portion of the periphery. False readings may be avoided by evacuating the chambers before and/or after they have passed through the testmg zone.

FIG. 5 shows a different embodiment wherein the star wheel or turnstile in the testing arrangement 33 is replaced by an endless chain 27 which is sealingly supported on a support base of generally rectangular configuration. A succession of laterally open chambers 26, functionally equivalent to chambers 7, are arranged about the periphery of the chain for receiving the successive containers which are fed to successive chambers at one end and removed therefrom at the diametrically opposite end after the chambers holding the containers have passed through a testing zone along the periphery of the moving chain. The testing zone is provided along one of the straight runs of the chain, at which point a sealing plate 28 is pressed laterally against the chambers by resilient pressure elements 29 to seal the chambers. Thus, any gas leaking out of a faulty container in a sealed chamber may be detected in the same manner as hereinabove described.

The operation of the testing arrangement of the embodiments of FIGS. 1 to 4 and 6 to 8 is well illustrated in the enlarged showings of FIGS. 9 and 10. As will be seen in FIG. 9, successive containers 1 are pushed from chute 15 into the pockets 5 of feeding wheel 6 which rotates clockwise towards the tangentially arranged star wheel 8 rotating counterclockwise. At the tangential touching point between the wheels, each container is transferred from a pocket 5 to the associated chamber 7 of the star wheel, the chambers 7 being laterally open in the cleansing zones A and B immediately ahead of, and behind, the transfer point so that any residual gasin the chambers may be removed in these zones before the chambers are sealed again as they are moved into the testing zone C. In this manner, faulty readings are avoided.

While FIG. 9 shows the modification of a moving sealing band 24, FIG. 10 illustrates the modification with the fixed sealing band 20. A sealing segment 25 could be substituted for either sealing means. In any of these modifications, the testing zone C is arranged towards the end of the sealed peripheral portion and the gas detectors are connected to the respective chambers in this zone. After the containers have passed the testing zone, they are removed from the chambers at point 32, for instance by a conveyor band moving in a direction opposite to that of the star wheel, or by a simple discharge chute 30.

Any leaky container that has been detected in the testing zone is signaled by the gas detecting means to the central indicating and control panel which, in dependence on the time required by the container to reach elimination point 31, actuates a plunger at this point which pushes the faulty container out of a registering opening in the chute wall to remove the same from the production line. If desired, a counter may also be used to control this elimination of faulty containers.

As will be seen in FIG. 10, a support base 16 supports star wheel 8 and provides a bottom sealing means for the chambers 7 of the wheel. Shaft 19 mounts the star wheel coaxially on the support base and sealing cover 17 over the star wheel provides a top sealing means for wheel chambers 7. The cover is fastened to the star wheel by screws 18. Lateral sealing of the chambers 7 is effected by sealing band 20 about a portion of the periphery of the wheel.

In the embodiment of FIG. 1 1, the star wheel 8' has a succession of bores 7' extending annularly adjacent the periphery of the wheel, the bores passing through the wheel and having open lower and upper ends. A conveyor screw 35, which is mounted below the wheel 8', feeds a succession of containers 1 to the feeding wheel 6 which is rotated counterclockwise to take along the containers fed into its pockets and delivers them to the star wheel 3' which is in tangential relationship with the feeding wheel. A lifting jack is associated with each bore 7', the lifting jacks rotating in unison with the star wheel 8 to remain in alignment with the bores. When the feeding wheel delivers a container onto a support platform 36 on the lifting jack, the same is raised to move the container upwardly into the associated bore, as shown in FIG. 12. The jack remains raised during the continuous rotation of wheel 8 until it has reached the point of removal of the container by discharge wheel 6', at which point the jack is lowered so that the container is taken along by the discharge wheel and removed from the apparatus, wheels 6 and 6' being substantially identical in structure and operation.

The platforms 36 serve as sealing means for closing the lower open ends of bores 7' while the upper open ends thereof are closed by means of replaceable holding sleeves 38 which are sealingly fitted over the upper ends of the bores to provide a chamber holding the container 11 during testing. Each sleeve carries a centering device 39 consisting of a tubular housing for rod 41 which is downwardly biased by spring 42 and whose lower end carries a centering clamp 40 receiving the top of container 1 and holding the same in centered position in sleeve 38. The holding sleeves may be readi- 1y replaced to adapt them to different sizes of containers.

As seen in FIGS. 12 and 13, a series of circumferential grooves 44 are provided in the periphery of the wheel 8', ports 45 in the grooves being in communication with the bores 7'. As the wheel 8' is rotated, the containers 1 in bores 7' are conveyed towards the testing zone C, any inflow of unwanted gases on the way to the testing zone being prevented by amounting an arcuate shield 50 over a large portion of the periphery of the wheel. While the shield 50 is sealingly close to the wheel periphery, it does not actually contact the same.

Spring-biased arms 43 are arranged to engage frictionally in grooves 44. As seen in FIG. 14, each arm 43 has an elongated chamber 46 with a port 48 to which is connected a flexible tube connecting the chamber 46 to control valve Sll, a gaseous fluidl line connecting the valve to vacuum installation 52. The arms 43 are vertically adjustably mounted on support column 49.

A gas detecting chamber 37 is arranged in the line between port 48 and valve 51. In this manner, if gas escapes from a faulty container held in a bore 7', it will leak through port 45 and on through port 48 into the gas detecting chamber 37 As can be seen in FIG. 13, the ports 45 are staggered in grooves 44 so that the gas detecting chambers 37 are placed in communication with each port 45 in succession, each chamber 7 being associated with a port 45. In this manner, the wheel 8 may be operated at a higher speed while the testing time and the period of regeneration for the gas detectors is extended, due also to the elongation of the chambers 46 in the arms 43. As soon as one of the ports 45 is in communication with a chamber 46, a control cam rotating in unison with wheel 8' actuates the corresponding control valve 51 connected to vacuum installation 52 so that the gas line leading from chamber 46 is evacuated and any gas escaping from chamber 7 may flow in gas detecting chamber 37.

It will be useful to arrange an ultrasonic detector ahead of screw conveyor 35 so that any grossly damaged containers 1 may be eliminated before they enter the testing apparatus and possibly damage it.

I claim:

I. An apparatus for testing the pressure resistance and fluid tightness of a succession of containers filled with a gaseous fluid under pressure, comprising 1. a heating means for the containers for elevating the temperature of the fluid in the containers,

2. a first conveyor means for conveying the succession of containers through the heating means for a time sufficient to permit the fluid temperature to be elevated,

3. a container feeding means receiving the containers in succession from the first conveyor means,

4. a second conveyor means arranged in substantially tangential relationship to the container feeding means and having a succession of chambers arranged peripherally for receiving successive ones of the containers from the feeding means, the second conveyor means revolving to move the chambers in a closed path and through a testing zone,

5. means for holding the successive containers in respective ones of the successive chambers and for sealing the chambers at least in said testing zone, and

6. means for testing containers for leakage in the testing zone arranged subsequent to the heating means,

7. means for removing the tested containers from the respective chambers beyond the testing zone.

2. The apparatus of claim 1, wherein the first conveyor means is a conveyor band, wherein the container feeding means is a rotary feeding wheel having a succession of pockets arranged about the periphery of the feeding wheel for receiving the successive containers from the conveyor band, and the second conveyor means is a rotary star wheel rotating in a direction opposite to that of the feeding wheel, the chambers being arranged annularly about the periphery of the star wheel and receiving the successive containers from the pockets of the feeding wheel.

3. The apparatus of claim 2, wherein the heating means comprises a trough having a bottom and containing a liquid heating medium, the conveyor band is a meandering band arranged at the bottom, an inclined plane guides the successive containers to the bottom of the trough at an inlet end of the conveyor band and an inclined plane guides the containers to the feeding wheel at an outlet end of the conveyor band, and further comprising an auxiliary trough in communication with the trough, and a heating medium level control means arranged between the trough and the auxiliary trough.

4. The apparatus of claim 2, further comprising a support base for the star wheel, the support base providing a bottom sealing means for the chambers, and the sealing means including a lateral sealing wall for the chambers, and fluid detecting means arranged in the testing zone adjacent the lateral sealing wall for detecting fluid escaped from the-containers held in the respective chambers in said zone.

5. The apparatus of claim 4, further comprising a shaft mounting the star wheel coaxially on the support base, a sealing cover over the star wheel providing a top sealing means for the chambers, and the lateral sealing wall including a sealing band extending about a large portion of the periphery of the star wheel.

6. The apparatus of claim 5, further comprising means fixedly holding one end of the sealing band, and resilient means for holding the other end of the sealing band to exert tension upon the band.

7. The apparatus of claim 6, wherein the resilient means is pneumatically operated.

8. The apparatus of claim 5, further comprising guide rollers supporting the sealing band for movement with the rotating star wheel.

9. The apparatus of claim 4, further comprising a shaft mounting the star wheel coaxially on the support base, a sealing cover over the star wheel providing a top sealing means for the chambers, and the lateral sealing wall including an upright sealing segment extending about a large portion of the periphery of the star wheel.

10. The apparatus of claim 2, wherein the chambers are defined by a succession of bores adjacent the periphery of the star wheel, the bores passing through the wheel and having open lower and upper ends, and wherein the sealing and holding means comprise pressure fluid operated closures operable for sealing the lower ends of the bores and replaceable holding devices for sealing the u per ends of the bores.

11. The apparatus 0 claim 10, wherein the holding devices comprise a sleeve fitting into the bores, and a container centering means associated with the sleeves and including a spring biased clamping rod extending into the sleeve.

12. The apparatus of claim 10, wherein the periphery of the star wheel defines a series of grooves, the bores being in communication with the grooves by ports leading from the bores to the grooves, and further comprising arms in frictional engagement with the grooves in the testing zone, the arms having chambers in communication with the grooves, a vacuum installation, lines connecting the chambers in the arms to the vacuum installation, control valve means in said lines for selectively connecting and disconnecting the vacuum installation from the chambers in the arms, and gas detecting chambers arranged in the lines between the chambers in the arms and the control valve means for detecting any escaped gases from the containers in the bores.

13. The apparatus of claim 12, wherein the chambers in the arms are elongated in the direction of rotation of the star wheel, these chambers being defined by elongated slots in the arms in contact with the grooves, and the lines including ports in the arms leading from the chambers in the arms to flexible tubes connecting the ports to the control valve means.

14. The apparatus of claim 13, wherein successive ones of the ports each associated with a respective one of the bores being staggered at intervals in the grooves.

15. The apparatus of claim 12, further comprising a support column vertically adjustably mounting the arms.

16. The apparatus of claim 1, wherein the second conveyor means comprises an endless chain having a succession of the chambers affixed to the chain, the chambers being laterally open at the periphery thereof, and the sealing means comprising a sealing plate and means for resiliently pressing the plate against the open sides of the chambers.

i i I I i 

1. An apparatus for testing the pressure resistance and fluid tightness of a succession of containers filled with a gaseous fluid under pressure, comprising
 1. a heating means for the containers for elevating the temperature of the fluid in the containers,
 2. a first conveyor means for conveying the succession of containers through the heating means for a time sufficient to permit the fluid temperature to be elevated,
 3. a container feeding means receiving the containers in succession from the first conveyor means,
 4. a second conveyor means arranged in substantially tangential relationship to the container feeding means and having a succession of chambers arranged peripherally for receiving successive ones of the containers from the feeding means, the second conveyor means revolving to move the chambers in a closed path and through a testing zone,
 5. means for holding the successive containers in respective ones of the successive chambers and for sealing the chambers at least in said testing zone, and
 6. means for testing containers for leakage in the testing zone arranged subsequent to the heating means,
 7. means for removing the tested containers from the respective chambers beyond the testing zone.
 2. a first conveyor means for conveying the succession of containers through the heating means for a time sufficient to permit the fluid temperature to be elevated,
 2. The apparatus of claim 1, wherein the first conveyor means is a conveyor band, wherein the container feeding means is a rotary feeding wheel having a succession of pockets arranged about the periphery of the feeding wheel for receiving the successive containers from the conveyor band, and the second conveyor means is a rotary star wheel rotating in a direction opposite to that of the feeding wheel, the chambers being arranged annularly about the periphery of the star wheel and receiving the successive containers from the pockets of the feeding wheel.
 3. The apparatus of claim 2, wherein the heating means comprises a trough having a bottom and containing a liquid heating medium, the conveyor band is a meandering band arranged at the bottom, an inclined plane guides the successive containers to the bottom of the trough at an inlet end of the conveyor band and an inclined plane guides the containers to the feeding wheel at an outlet end of the conveyor band, and further comprising an auxiliary trough in communication with the trough, and a heating medium level control means arranged between the trough and the auxiliary trough.
 3. a container feeding means receiving the containers in succession from the first conveyor means,
 4. a second conveyor means arranged in substantially tangential relationship to the container feeding means and having a succession of chambers arranged peripherally for receiving successive ones of the containers from the feeding means, the second conveyor means revolving to move the chambers in a closed path and through a testing zone,
 4. The apparatus of claim 2, further comprising a support base for the star wheel, the support base providing a bottom sealing means for the chambers, and the sealing means including a lateral sealing wall for the chambers, and fluid detecting means arranged in the testing zone adjacent the lateral sealing wall for detecting fluid escaped from the containers held in the respective chambers in said zone.
 5. The apparatus of claim 4, further comprising a shaft mounting the star wheel coaxially on the support base, a sealing cover over the star wheel providing a top sealing means for the chambers, and the lateral sealing wall including a sealing band extending about a large portion of the periphery of the star wheel.
 5. means for holding the successive containers in respective ones of the successive chambers and for sealing the chambers at least in said testing zone, and
 6. means for testing containers for leakage in the testing zone arranged subsequent to the heating means,
 6. The apparatus of claim 5, further comprising means fixedly holding one end of the sealing band, and resilient means for holding the other end of the sealing band to exert tension upon the band.
 7. The apparatus of claim 6, wherein the resilient means is pneumatically operated.
 7. means for removing the tested containers from the respective chambers beyond the testing zone.
 8. The apparatus of claim 5, further comprising guide rollers supporting the sealing band for movement with the rotating star wheel.
 9. The apparatus of claim 4, further comprising a shaft mounting the star wheel coaxially on the support base, a sealing cover over the star wheel providing a top sealing means for the chambers, and the lateral sealing wall including an upright sealing segment extendIng about a large portion of the periphery of the star wheel.
 10. The apparatus of claim 2, wherein the chambers are defined by a succession of bores adjacent the periphery of the star wheel, the bores passing through the wheel and having open lower and upper ends, and wherein the sealing and holding means comprise pressure fluid operated closures operable for sealing the lower ends of the bores and replaceable holding devices for sealing the upper ends of the bores.
 11. The apparatus of claim 10, wherein the holding devices comprise a sleeve fitting into the bores, and a container centering means associated with the sleeves and including a spring biased clamping rod extending into the sleeve.
 12. The apparatus of claim 10, wherein the periphery of the star wheel defines a series of grooves, the bores being in communication with the grooves by ports leading from the bores to the grooves, and further comprising arms in frictional engagement with the grooves in the testing zone, the arms having chambers in communication with the grooves, a vacuum installation, lines connecting the chambers in the arms to the vacuum installation, control valve means in said lines for selectively connecting and disconnecting the vacuum installation from the chambers in the arms, and gas detecting chambers arranged in the lines between the chambers in the arms and the control valve means for detecting any escaped gases from the containers in the bores.
 13. The apparatus of claim 12, wherein the chambers in the arms are elongated in the direction of rotation of the star wheel, these chambers being defined by elongated slots in the arms in contact with the grooves, and the lines including ports in the arms leading from the chambers in the arms to flexible tubes connecting the ports to the control valve means.
 14. The apparatus of claim 13, wherein successive ones of the ports each associated with a respective one of the bores being staggered at intervals in the grooves.
 15. The apparatus of claim 12, further comprising a support column vertically adjustably mounting the arms.
 16. The apparatus of claim 1, wherein the second conveyor means comprises an endless chain having a succession of the chambers affixed to the chain, the chambers being laterally open at the periphery thereof, and the sealing means comprising a sealing plate and means for resiliently pressing the plate against the open sides of the chambers. 